TWI818279B - A solid polymer composition, a self-supporting film and a light emitting device - Google Patents

Abstract

The invention refers in a first aspect to self-supporting film comprising green luminescent crys-tals (1), red luminescent crystals (2), and a polymer (3). The green luminescent crystals (1) are perovskite crys-tals. The red luminescent crystals (2) are zincblende or wurzite, preferably zincblende, crystals. A second aspect of the invention refers to a solid polymer composition (100). A third aspect of the invention refers to a light emitting device comprising either the solid polymer composition (100) or the self-supporting film.

Description

Solid polymer composition, self-supporting film and light-emitting device

The present invention relates to a solid polymer composition, a self-supporting film including the solid polymer composition, and a light-emitting device including the solid polymer composition or the self-supporting film.

The most advanced liquid crystal displays (LCDs) or display components contain components based on light-emitting crystals (quantum dots). In particular, the backlight component of such an LCD may include an RGB backlight composed of red light, blue light and green light. Nowadays, luminescent crystals (quantum dots) are generally used to produce the backlight color of such backlight components. Document US 2017/186922 A1 discloses an electronic device, which includes a light source having peak emission at a wavelength between about 440 nm and about 480 nm; and a light conversion layer disposed on the light source. The light conversion layer includes a first quantum dot that emits red light and a second quantum dot that emits green light. At least one of the first quantum dot and the second quantum dot has a perovskite crystal structure and includes a compound represented by Chemical Formula 1: AB'X _{3+ α} , wherein A is a Group IA metal, NR ₄ ⁺ , or a combination thereof , B' is a group IVA metal, X is a halogen, BF ₄ ⁻ , or a combination thereof, and α is 0 to 3. Document WO 2017/195062 A1 discloses devices and systems including materials including halide perovskites and/or phosphors for production and/or communications using visible light, and the like. Document WO 2018/146561 A1 discloses compositions and methods related to light-converting luminescent composite materials. Document WO 2017/108568 A1 discloses that the light-emitting component includes a first film and a second film. The first film includes a first solid polymer composition, and the second film includes a second solid polymer composition. The first solid polymer composition includes a first luminescent crystal. The second solid polymer composition includes a second luminescent crystal. The size of the first luminescent crystal is between 3 nm and 3000 nm, and emits red light in response to excitation by shorter wavelength light. The size of the second luminescent crystal is between 3 nm and 3000 nm, and emits green light in response to excitation by shorter wavelength light. Document WO 2020/130592 A1 relates to a metal halide perovskite light-emitting device and its manufacturing method. According to the present invention, a metal halide perovskite light-emitting device uses a perovskite film having a multi-dimensional crystal structure derived from a proton transfer reaction as the light-emitting layer, so that ion transfer is suppressed by a self-assembled shell and surface defects are eliminated are removed, thereby improving photoluminescence intensity, luminous efficiency, and lifetime. In addition, high-efficiency light-emitting devices can be manufactured by injecting fluorine-based materials and base materials into the PEDOT:PSS conductive polymer that has been used as a hole injection layer to adjust its acidity and improve the work function of the interface, and through chemically stable Graphene barrier layer to protect electrodes susceptible to acid corrosion. Manufacturing of such components presents various challenges. One challenge involves embedding light-emitting crystals into components. Due to the different chemical properties of the luminescent crystals, there may be incompatibilities between various embedding materials containing the luminescent crystals or even between luminescent crystals embedded in the same material. This incompatibility may cause degradation of materials in the display components and therefore may affect the service life of such displays. In addition, devices based on light-emitting crystals often face stability and brightness challenges, where it is difficult for these devices to achieve good stability and high display brightness.

The problem to be solved by the present invention is to overcome the shortcomings of the prior art. In particular, the present invention overcomes the shortcomings of the prior art in terms of stability and brightness. Unless otherwise stated, the following definitions shall apply in this specification: The terms "a", "an", "the" and similar terms used in this description are to be construed as encompassing Both the singular and the plural are used unless otherwise indicated herein or otherwise clearly contradicted by the context. The term "comprising" shall include the entirety of "comprises", "consisting essentially of" and "consisting of". Unless otherwise indicated herein or otherwise clearly contradicted by context, percentages are given in weight %. "Independently" means that a substituent/ion may be selected from one of the specified substituents/ions, or may be a combination of more than one of the above-mentioned substituents/ions. The term " luminescent crystal " (LC) is known in the art and in the context of the present invention relates to crystals of 2 to 100 nm made of semiconductor materials. The term includes quantum dots, typically in the range of 2 to 10 nm, and nanocrystals, typically in the range of 10 to 100 nm. As the term suggests, LC displays luminescence. In the context of the present invention, the term luminescent crystal includes both single crystal and polycrystalline particles. In the latter case, a particle can be composed of several crystal domains (grains) connected by crystalline or amorphous phase interfaces. Luminescent crystals are semiconductor materials that exhibit a direct band gap (typically in the range of 1.1 to 3.8 eV, more typically 1.4 to 3.5 eV, even more typically 1.7 to 3.2 eV). After irradiation with electromagnetic radiation equal to or higher than the band gap, electrons in the valence band are excited to the conduction band, leaving holes in the valence band. The formed excitons (electron-hole pairs) then undergo radiative recombination in the form of photoluminescence, with maximum intensity concentrated around the LC band gap value and exhibiting a photoluminescence quantum yield of at least 1%. When in contact with external sources of electrons and holes, LC can exhibit electroluminescence. The term " quantum dot " (QD) is known and relates particularly to semiconductor nanocrystals, the diameter of which is generally between 2 and 10 nm. In this range, the physical radius of QD is smaller than the main excitation Bohr radius, causing the quantum confinement effect to dominate. As a result, the electronic state of the QD and therefore the band gap is a function of the composition and physical size of the QD, ie, the color absorbed/emitted is related to the QD size. The optical quality of QD samples is directly related to their homogeneity (more monodisperse QDs will have smaller emission half-maximum (FWHM)). When QDs reach sizes larger than the Bohr radius, quantum confinement effects are hindered and the sample may no longer emit light because the non-radiative path for exciton recombination may become dominant. QDs are therefore a specific subgroup of nanocrystals, specifically defined by their size and size distribution. Typical quantum dot compositions include cadmium or indium, for example in the form of cadmium selenide (CdSe) or indium phosphide (InP). The term " core - shell crystal " is known, and relates particularly to quantum dots, generally having a CdSe core or an InP core, which typically contains zinc sulfide (ZnS), zinc selenide (ZnSe), cadmium sulfide (CdS) or combination thereof with additional shells. The term " core - shell quantum dot platelet " is known and relates in particular to core-shell quantum dots having a thin-layer structure. The aspect ratio (longest:shortest direction) of the lamellae in all 3 orthogonal dimensions ranges from 2 to 50, preferably from 3 to 20, most preferably from 4 to 15. The term " perovskite crystal " is known and includes in particular crystalline compounds of perovskite structure. The perovskite structure itself is known and is described as a cubic, pseudocubic, tetragonal or orthorhombic crystal with the general formula M1M2X3, where M1 is a coordination number of 12 (cubic octahedral) (cuboctaeder), M2 is a cation with a coordination number of 6 (octaeder), and X is an anion with a cubic, pseudo-cubic, square or orthorhombic lattice. In these structures, selected cations or anions can be replaced by other ions (randomly or regularly up to 30 atomic %), resulting in doped perovskites or non-stoichiometric perovskites while still maintaining their original crystal structure. Preferably, the luminescent perovskite crystals are approximately equiaxed (such as spherical or cubic). A particle is said to be approximately equiaxed if the aspect ratio (longest:shortest direction) of all 3 orthogonal dimensions ranges from 1 to 2. Therefore, the components of the LC preferably contain 50 to 100% (n/n), preferably 66 to 100% (n/n), and more preferably 75 to 100% (n/n) equiaxed nanometers. crystal. The production of such luminescent perovskite crystals is known, for example, from WO2018 028869. The term " polymer " is well-known and includes organic and inorganic synthetic materials containing repeating units ("monomers"). The term polymer includes homopolymers and copolymers. Furthermore, it includes cross-linked polymers and non-cross-linked polymers. Depending on the context, the term polymer shall include its monomers and oligomers. Polymers include, for example, acrylate polymers, carbonate polymers, polyester polymers, epoxy polymers, vinyl polymers, urethane polymers, imide polymers, ester polymers, furan polymers, melamine Polymers, styrene polymers, norbornene polymers, silazane polymers, polysiloxane polymers and cyclic olefin copolymers. The polymer may include other materials known in the art, such as polymerization initiators, stabilizers, fillers, and solvents. Polymers can be further characterized by physical parameters such as polarity, glass transition temperature Tg, Young's modulus, and light transmittance. Transmittance: In general, the polymers used in the context of the present invention are light-transmissive for visible light, ie non-opaque, to allow the possibility of light emitted by the luminescent crystal and the light source used to excite the luminescent crystal. of light passing through. The light transmittance can be determined by white light interferometry or UV-Vis spectroscopy. Glass transition temperature: (Tg) is a parameter recognized in the polymer field; it describes the temperature at which an amorphous or semi-crystalline polymer changes from a glassy (hard) state to a more flexible, compliant or rubbery state. Polymers with a high Tg are considered "hard", while polymers with a low Tg are considered "soft". At the molecular level, Tg is not a discrete thermodynamic shift, but a temperature range in which the mobility of polymer chains increases significantly. However, it is conventional to describe a single temperature defined as the midpoint of a temperature range bounded by the tangent between two flat areas of the heat flow curve measured by DSC. Tg can be determined using DSC according to DIN EN ISO 11357-2 or ASTM E1356. This method is particularly suitable if the polymer is present in the form of bulk material. Alternatively, Tg can be determined by measuring micron or nanohardness as a function of temperature using micron or nanoindentation according to ISO 14577-1 or ASTM E2546-15. This method is suitable for the light-emitting components and lighting devices disclosed herein. Suitable analytical equipment is available from MHT (Anton Paar), Hysitron TI Premier (Bruker) or Nano Indenter G200 (Keysight Technologies). Data obtained through temperature-controlled micro- and nanoindentation can be converted into Tg. Generally speaking, the change in work of plastic deformation or Young's modulus or hardness with temperature is measured, and Tg is the temperature at which these parameters change significantly. Young's modulus or elastic modulus is a mechanical property that measures the stiffness of a solid material. It defines the relationship between stress (force per unit area) and strain (proportional deformation) of a material within the linear elastic range of uniaxial deformation. A first aspect of the present invention relates to a solid polymer composition including green luminescent crystals, red luminescent crystals and polymers. The green luminescent crystal is a perovskite crystal, which is selected from compounds of formula (I): [M ¹ A ¹ ] _a M ² _b X _c (I), where: A ¹ represents one or more organic cations, in particular It is formamidinium (FA), M ¹ represents one or more alkali metals, especially Cs, M ² represents one or more metals other than M ¹ , especially Pb, X represents one or more metals selected from halide, pseudo Anions of the group consisting of halides and sulfides, in particular Br, a represents 1 to 4, b represents 1 to 2, c represents 3 to 9, and M ¹ , or A ¹ , or M ¹ and ^A1 . In a further advantageous embodiment of the invention, the green luminescent crystal is a green luminescent perovskite crystal of formula (I'): FAPbBr ₃ (I'). In particular, formula (I) describes a perovskite luminescent crystal that, after absorbing blue light, emits light with a wavelength between 500 nm and 550 nm in the green light spectrum, specifically light concentrated around 527 nm. Red-emitting crystals are known which emit red light (630nm +/- 30nm) in response to excitation by shorter wavelength light. Suitable crystal systems are selected from the group of semiconductor compounds of groups II to VI and the group of semiconductor compounds of groups III to V. In embodiments, the crystals are crystallized in a zinc blende lattice structure ("zincblende crystal") or in a wurtzite crystal structure ("wurtzite crystal"), preferably zincblende -type. . Both structures share a common cation:anion ratio = 1:1, where the anions form closely packed equal spheres (hcp or fcp, respectively) and the cations are located in tetraeder positions. In embodiments, the crystal system is selected from compounds of formula (II): [M ³ M ³ '][YY'] (II), wherein: M ³ and M ³ ' represent Al, Ga, In, especially In , and Y and Y' represent N, P, As, Sb, especially P, and M3' and Y' may or may not exist (i.e. III to V group semiconductor compounds), or M ³ and M ³ ' represent Zn , Cd, Be, especially Cd, and Y, Y' represent S, Se, Te, especially Se, and M3', Y' may or may not exist (ie, II to VI semiconductor compounds). It is obvious from the above that suitable crystals include binary compounds of formula (II-1), ternary compounds of formulas (II-2) and (II-3) and quaternary compounds of formula (II-4) [M ³ ][Y] (II-1), where: M ³ and Y are as defined above, such as CdSe, InN, InP, InAs, and InSb; [M ³ M ³ '][Y] (II-2), where : M ³ , M ³ ', and Y are as defined above, and M ³ and M ³ ' exist, such as InGaP; [M ³ ][YY'] (II-3), where: M ³ , Y, Y ' is as defined above, and M ³ , Y, Y' exist, such as InPN, InPAs, and InPSb; [M ³ M ³ '][YY'] (II-4), where: M ³ , M ³ ', Y, Y' are as defined above, and M ³ , M ³ ', Y, Y' are present, such as InGaPN, InGaPAs, and InGaPSb. Suitable crystals may or may not be surrounded by a shell. A crystal surrounded by a shell is called a core - shell crystal . In such core-shell crystals, the compounds that form the core and the compounds that form the shell are different. Suitable crystals may or may not be doped with doping metals . Suitable dopants are known in the art and typically have concentrations in the range of 1 mol% or less. The crystal size of red-emitting crystals can vary within a wide range, but is generally within the range of 1 to 10 nm. Such crystals are called quantum dots, which are distinguished from microcrystals. For Group II to VI semiconductor compounds, a suitable range is 1 to 10 nm, preferably 3 to 8 nm. For III to V semiconductor compounds, a suitable range is 1 to 8 nm, preferably 2 to 4 nm. Preferably, the luminescent crystal displays a monodisperse size distribution. In the context of the present invention, the term "monodisperse" refers to a population of quantum dots that is at least about 60% of the population, preferably 75% to 90% of the population, or any integer or non-integer range therebetween. into the specified particle size range. The diameter deviation of the monodisperse particle population is less than 20% root-mean-square (rms), preferably less than 10% rms, and most preferably less than 5% rms. Particle size and particle size distribution can be determined by microscopy. The shape of the crystal can change into thin layer type, cubic, spherical, and polyhedral. In a further advantageous embodiment of the invention, the red luminescent crystal is of the core-shell type, having a core as defined in claim 1 and a shell of the formula (III): M ⁴ Z (III), where: M ⁴ represents Zn Or Cd, preferably Zn, and Z represents S, Se, Te, and the compounds of formula (III) and formula (II) are different. Shells include single-shell and multi-shell structures. In a further advantageous embodiment of the invention, the red-emitting crystal contains a core selected from the group consisting of InP and CdSe. In addition, the red luminescent crystal includes a single shell selected from the group consisting of ZnS, ZnSe, ZnSeS and ZnTe. Specific examples include InP@ZnS, InP@ZnSe, InP@ZnSeS, InP@ZnSeS, InP@ZnSe@ZnS, CdSe@ZnS and CdSe@ZnSe, in particular InP@ZnSeS. Furthermore, the red luminescent crystal includes a multi-shell selected from a combination of compounds selected from the group consisting of ZnS, ZnSe, ZnSeS and ZnTe. Specific examples include InP/ZnSe/ZnS (multi-shell) and InP/ZnSeS/ZnS (multi-shell). In a further advantageous embodiment of the invention, the red-emitting crystal contains a CdSe core alloyed/doped with Zn. This embodiment allows reducing the amount of Cd per quantum dot. In a further advantageous embodiment of the invention, the concentration of M ² is from 100 to 1000 ppm, preferably from 300 to 1000 ppm, very preferably from 500 to 1000 ppm, and/or the concentration of M ³ + M ³ ' is from 300 to 1000 ppm. 2,500ppm, preferably 600 to 2,000ppm, very preferably 1,200 to 1,700ppm, and/or the red core-shell quantum dots have a thin layer structure. In a further advantageous embodiment of the invention, the concentration of M ³ +M ³ ' is >300 ppm, preferably >600 ppm, most preferably >1,200 ppm, and/or the red core-shell quantum dots have a thin layer structure. A solid polymer composition according to another advantageous embodiment of the present invention, wherein the particle size _sp of the red core-shell quantum dots is 1 nm ≤ _sp ≤ 10 nm, in particular 3 nm ≤ _sp ≤ 8 nm, in particular 2nm ≤ _sp ≤ 6nm, particularly 2nm ≤ _sp ≤ 4nm. In a further advantageous embodiment of the invention, the polymer has a molar ratio z of the sum of (oxygen + nitrogen) to carbon, where z ≤ 0.9, z ≤ 0.75, in particular z ≤ 0.4, in particular z ≤ 0.3 , especially z ≤ 0.25. In a further advantageous embodiment, the polymer contains an acrylate, very particularly wherein the polymer contains a cyclic aliphatic acrylate. In an advantageous embodiment, the solid polymer comprises an acrylate selected from the following list: isocamphenyl acrylate (CAS 5888-33-5), isocamphenyl methacrylate (CAS 7534-94-3 ), dicyclopentyl acrylate (CAS 79637-74-4, FA-513AS (Hitachi Chemical, Japan)), dicyclopentyl methacrylate (CAS 34759-34-7, FA-513M (Hitachi Chemical, Japan) ), 3,3,5-trimethylcyclohexyl acrylate (CAS 86178-38-3), 3,3,5-trimethylcyclohexyl methacrylate (CAS 7779-31-9), acrylic acid 4 -Tertiary butylcyclohexyl ester (CAS 84100-23-2), 4-tertiary butylcyclohexyl methacrylate (CAS 46729-07-1). In another advantageous embodiment, the solid polymer is cross-linked. In another advantageous embodiment, the solid polymer contains multifunctional acrylates. In a further advantageous embodiment, the solid polymer composition has a glass transition temperature _Tg such that _Tg ≤ 120°C, in particular _Tg ≤ 100°C, in particular _Tg ≤ 80°C, in particular _Tg ≤ 70℃. The respective T _g was measured according to DIN EN ISO 11357-2:2014-07 during the second heating cycle, starting from -90°C up to 250°C and applying a heating rate of 20 K/min. In a further advantageous embodiment of the invention, the solid polymer composition comprises scattering particles selected from the group consisting of metal oxide particles and polymer particles, preferably selected from the group consisting of TiO ₂ , ZrO ₂ , Al ₂ A group consisting of O ₃ and organopolysiloxane. In a further advantageous embodiment of the invention, the solid polymer is semi-crystalline. In a further advantageous embodiment of the invention, the melting temperature of the solid polymer is <140°C, preferably <120°C, most preferably <100°C. A second aspect of the invention relates to a self-supporting film comprising the solid polymer composition according to the first aspect of the invention. The self-supporting film emits green and red light in response to excitation by light with a wavelength shorter than the emitted green light. In an advantageous embodiment of the self-supporting film, the solid polymer composition is sandwiched between two barrier layers. In particular, this sandwich arrangement refers to an arrangement with a barrier layer, a polymer and another barrier layer in the horizontal direction. The two barrier layers of the sandwich structure can be made of the same barrier layer material or different barrier layer materials. The technical effect of the barrier layer is to improve the stability of the luminescent perovskite crystal, especially to oxygen or moisture. In particular, such barrier layers are known in the art and generally include those with low water vapor transmission rate (WVTR) and/or low oxygen transmission rate (OTR). Material/material combination. By selecting this material, degradation of the luminescent crystals in the device in response to exposure to water vapor and/or oxygen can be reduced or even avoided. The barrier layer or barrier film preferably has a WVTR of less than 10 (g)/(m ² *day) at a temperature of 40°C/90% rh and atmospheric pressure, and more preferably less than 1 (g)/( m ² *day), and the optimal system is less than 0.1(g)/(m ² *day). In one embodiment, the barrier film is impermeable to oxygen at a temperature of 23°C/90% rh and atmospheric pressure, and the OTR (oxygen transmission rate) is >0.1 (mL)/(m ² *day ), more preferably >1 (mL)/(m ² *day), optimally >10 (mL)/(m ² *day). In one embodiment, the thickness of the barrier film is >0.3 mm, more preferably >1 mm, most preferably >3 mm. In one embodiment, the barrier film is transparent to light, that is, the visible light transmittance is >80%, preferably >85%, and most preferably >90%. A suitable barrier film may be present as a single layer. Such barrier films are known in the art and contain glasses, ceramics, metal oxides and polymers. Suitable polymers may be selected from the group consisting of polyvinylidene chloride (PVdC), cycloolefin copolymer (COC), ethylene vinyl alcohol (EVOH), high density polyethylene (HDPE) and polypropylene (PP) ; Suitable inorganic materials may be selected from the group consisting of metal oxides, SiOx, SixNy, and AlOx. Optimally, the polymeric humidity barrier material contains a material selected from the group of PVdC and COC. Most advantageously, the polymeric oxygen barrier material contains a material selected from EVOH polymers. Suitable barrier films can be present in multiple layers. Such barrier films are known in the art and typically comprise a substrate such as PET with a thickness in the range of 10 to 200 µm, and a thin inorganic layer comprising a material from the group of SiOx and AlOx, or Organic layers based on liquid crystals embedded in a polymer matrix, or polymers with desired barrier properties. Possible polymers for such organic layers include, for example, PVdC, COC, EVOH. Another advantageous embodiment of the invention is that the self-supporting film has a haze h ₁ of 10 ≤ h ₁ ≤ 80%, preferably 20 ≤ h ₁ ≤ 70%, most preferably 30 ≤ h ₁ ≤ 60% ; and/or the concentration of M ² is 5 to 200 mg/m ² , preferably 10 to 100 mg/m ² , 20 to 80 mg/m ² , most preferably 30 to 80 mg/m ² ; and/or M ³ The concentration of +M ³ ' is 30 to 250 mg/m ² , preferably 60 to 200 mg/m ² , and most preferably 120 to 170 mg/m ² . In a further advantageous embodiment of the invention, the concentration of M ³ + M ³ ' is >30 mg/m ² , preferably >60 mg/m ² , most preferably >120 mg/m ² . In a further advantageous embodiment of the invention, the haze h ₂ of the self-supporting film is h ₂ ≤ 80%, preferably h ₂ ≤ 70%, less preferably h ₂ ≤ 60%. In a further advantageous embodiment of the invention, the self-supporting film has a haze h ₂ of 10% ≤ h ₂ ≤ 80%, preferably 20% ≤ h ₂ ≤ 70%, very preferably 30% ≤ h ₂ ≤ 60%. Haze in the context of the present invention means transmission haze. Transmitted haze is the amount of light that undergoes wide angle scattering (Wide Angle Scattering) when passing through a transparent material (in this case, a self-supporting film), usually at an angle greater than 2.5° to the normal direction of incidence (measured by ASTM D1003; For example, BYK Gardner haze meter). The low haze of the self-supporting film has the technical effect of making the luminescent perovskite crystals in the self-supporting film more stable, especially when they are exposed to blue light sources. The stability is a result of reduced multiplex scattering of blue light in the self-supporting film due to lower haze. In addition, another technical effect of low haze is that lower haze results in higher display brightness, measured as the "light conversion factor" (LCF) of the self-supporting film. The light conversion factor of a self-supporting film refers to the ratio of the intensity of green light emitted in the vertical direction from the self-supporting film to the intensity of blue light that is extinguished (e.g., absorbed, reflected, or scattered) in the vertical direction of the self-supporting film. In further advantageous embodiments, the thickness of such a self-supporting film may generally range from 0.005 to 10 mm, more preferably from 0.05 to 3 mm, most preferably from 0.01 to 0.5 mm. In a further advantageous embodiment of the self-supporting film, the green luminescent crystals are arranged in a first region of the solid polymer composition and the red luminescent crystals are arranged in a second region of the solid polymer composition. In particular, the first region and the second region are suitable for forming layers adjacent to each other. In a further advantageous embodiment, the first area and the second area may be arranged spaced apart from each other. A third aspect of the invention relates to a light-emitting device, in particular to a liquid crystal display (LCD). Advantageously, the light-emitting device comprises a solid polymer composition according to the first aspect of the invention. In a further advantageous embodiment, the light-emitting device comprises a self-supporting film according to the second aspect of the invention. A further advantageous embodiment of the light emitting device includes an array of more than one blue LED. In addition, the LED array basically covers the entire LCD display area. A diffusion plate is disposed between the array of more than one blue LED and the self-supporting film. In a further advantageous embodiment of the invention, one or more blue LEDs of the array are each adapted to switch on and off with a frequency f of f ≥ 150 Hz, preferably f ≥ 300 Hz, very preferably f ≥ 600 Hz. switch between. Other advantageous embodiments are listed in the dependent claims and in the description below.

Embodiments, examples, experiments, aspects and advantages of representing or leading to embodiments of the present invention will be better understood from the following detailed description thereof. This description refers to the accompanying drawings, in which: Figure 1 shows a schematic diagram of a solid polymer composition 100 according to an embodiment of the first aspect, wherein the solid polymer composition includes a green luminescent crystal 1 of formula (I), (II) Red luminescent crystal 2 and polymer 3. Additional embodiments of the solid polymer composition of Figure 1 may include additional features in accordance with the first aspect of the invention. FIG. 2 shows a schematic diagram of an embodiment of a self-supporting film according to a second aspect of the invention. In an advantageous embodiment as shown, the self-supporting film may comprise a barrier layer 4 sandwiching a solid polymer composition 100. FIG. 3 shows a schematic diagram of an embodiment of a light-emitting device according to a third aspect of the present invention, particularly a liquid crystal display (LCD). Advantageously, the light emitting device comprises a solid polymer composition 100 as shown in Figure 1 or a self-supporting film as shown in Figure 2. Advantageously, the lighting device contains more than one blue LED 6, wherein the LEDs cover substantially the entire liquid crystal display area 5. In particular, a diffusion plate (the diffusion plate is not shown in the figure) is arranged between the array of one or more blue LEDs and the self-supporting film. In particular, the light emitting device may emit light of RGB colors (aa, bb, cc). Figure 4 shows a further advantageous embodiment of a self-supporting film according to a second aspect of the invention. In this embodiment, the green light-emitting crystal 1 is arranged in the first region 11 of the self-supporting film. The red luminescent crystal 2 is arranged in the second region 21 of the self-supporting film. The first region 11 and the second region 21 form adjacent layers. Experimental Part Example 1 : Preparation of self-supporting films using polymers with glass transition temperature and low haze. Green perovskite luminescent crystals with a composition of formamidinium lead tribromide (FAPbBr ₃ ) were synthesized in toluene as follows: lead tribromide formamidinium (FAPbBr ₃ ) was prepared by grinding PbBr ₂ and Synthesized from FABr. That is, 16 mmol PbBr ₂ (5.87 g, 98% ABCR, Karlsruhe (DE)) and 16 mmol FABr (2.00 g, Greatcell Solar Materials, Queanbeyan, (AU)) were mixed with yttrium-stabilized zirconia beads (zirconia beads) ( diameter 5mm) for 6 hours to obtain pure cubic FAPbBr ₃ , which was confirmed by XRD. Orange FAPbBr ₃ powder was added to oleylamine (80 to 90, Acros Organics, Geel (BE)) (weight ratio FAPbBr ₃ : oleylamine = 100:15) and toluene (>99.5%, puriss, Sigma Aldrich). The final concentration of FAPbBr ₃ was 1 wt%. The mixture was then ball-milled using yttrium-stabilized zirconia beads with a diameter of 200 µm under ambient conditions (if not otherwise defined, the ambient conditions for all experiments were: 35°C, 1 atm, in air) mill) for 1 hour to disperse, and a green luminous ink was obtained. Film formation : 0.1 g of green ink was mixed with a UV curable monomer/cross-linker mixture (0.7 g FA-513AS, Hitachi Chemical, Japan/0.3 g Miramer M240, Miwon, Korea) in a high-speed mixer containing 1 wt% photoinitiator diphenyl (2,4,6-trimethylbenzyl)phosphine oxide (TCI Europe, Netherlands), and 2 wt% polymer scattering particles (organopolysiloxane, ShinEtsu , KMP-590), and red luminescent crystals of equiaxed core-shell QDs with InP core and ZnS shell suspended in toluene, and toluene was evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was then coated with a 50 μm thick layer on a 100 μm barrier film (Supplier: I-components (Korea); Product: TBF-1007) and then laminated with a second barrier film of the same type. Afterwards, the laminated structure was UV cured for 60 seconds (UVAcube100, equipped with mercury lamp and quartz filter, Hoenle, Germany). The Pb concentration in the solidified layer (without barrier layer) was 500 ppm Pb, and the Pb loading per area was 30 mg Pb/m ² . The In concentration in the solidified layer (without barrier layer) was 1300 ppm In, and the In loading per area was 80 mg In/m ² . The initial properties of the film obtained showed a green emission wavelength of 526 nm with a FWHM of 22 nm, and a red emission wavelength of 630 nm with a FWHM of 20 nm. When placed on a blue LED light source (450nm emission wavelength), the color coordinates (CIE1931) of the film are x=0.25 and y=0.20. There are two cross prism sheets (X-BEF) and an intensifier on the top of the QD film. Bright Film (DBEF) (Optical properties measured with Konica Minolta CS-2000). The resulting film had a haze of 50% and a transmittance of 85% (measured with a BYK Gardner haze meter). The light conversion factor of the film is 49% (LCF; LCF = green intensity of emission (integrated emission peak) divided by the reduction of blue intensity (integrated emission peak); vertical emission of green and blue of QD film using Konica Minolta CS -2000 to measure). The glass transition temperature Tg of the UV-cured solid polymer composition is determined by DSC according to DIN EN ISO 11357-2:2014-07. The starting temperature is -90°C, the ending temperature is 250°C, and the heating rate is 20 K /min, in a nitrogen atmosphere (20 ml/min). Purge gas system 20 ml/min nitrogen (5.0). The DSC system DSC 204 F1 Phoenix (Netzsch) is used. _Tg was determined at the second heating cycle (the first heating from -90°C to 250°C showed an overlapping effect in addition to glass transfer). For DSC measurements, the solid polymer composition was removed from the film by delaminating the barrier film. The measured Tg of the UV-cured resin composition is 75°C. By placing the film into a light box with high blue light intensity (supplier: Hoenle; model: LED CUBE 100 IC), the blue flux on the film is 410 mW/cm ² and the film temperature is 50°C. The stability of the film was tested under LED light irradiation for 150 hours. Additionally, the membranes were tested in a climate chamber at 60°C and 90% relative humidity for 150 hours. Changes in optical parameters after film stability testing were measured using the same procedure as for measuring initial properties (described above). The changes in optical parameters are as follows: These results show that when tested under high blue flux and high temperature/high humidity conditions, both green perovskite crystals and red core-shell quantum dots show good chemical compatibility and high stability, and can achieve self-supporting luminescence. membrane. Comparative Example 1 of Example 1 : A self-supporting film was prepared using a polymer with low glass transition temperature and high haze. The procedure is the same as the previous one in Example 1, except that the following parameters are changed: • Only 50% of green perovskite QDs and red core-shell InP quantum dots are used • 12 wt% of scattering particles KMP-590 are mixed to UV curable acrylate mixture to increase the haze of the final QD film. The obtained self-supporting film showed similar optical properties and Tg as Example 1, but with a haze of 95%, a transmission of 80% and an LCF of 41%. It can be seen that the LCF is lower than Experiment 1. Higher haze leads to lower LCF, while lower haze leads to higher LCF. Therefore, the lower haze of the QD film is conducive to having a higher LCF, and thus a higher display efficiency (under a specific equivalent white point color coordinate). The Pb concentration in the solidified layer (without barrier layer) was 250 ppm Pb, and the Pb loading per area was 15 mg Pb/m ² . The In concentration in the solidified layer (without barrier layer) was 650 ppm In, and the In loading per area was 40 mg In/m ² . The same stability test as Example 1 was performed again, and the optical parameters changed as follows: These results show that compared to Example 1, the higher haze of the QD film leads to a decrease in the stability of the green perovskite crystal under high blue flux (a decrease in green intensity as seen from the decrease in y value), especially Green perovskite crystals are less stable at high blue fluxes. Therefore, QD films with low haze are advantageous, which lead to improved stability of the QD film under high blue flux so as to have stable color coordinates and stable white point during the operating life of the display device. Comparative Example 2 of Example 1 : Preparation of a self-supporting film using a polymer with high glass transition temperature and low haze. The procedure was the same as in Example 1, except that the acrylate monomer mixture (0.7 g FA-513AS, Hitachi Chemical, Japan/0.3 g Miramer M240, Miwon, Korea) was replaced by the following acrylate monomer mixture: • 0.7g FA-DCPA, Hitachi Chemical, Japan/0.3g FA-320M, Hitachi Chemical, Japan. The obtained self-supporting film showed similar optical properties and haze to Example 1, but with a Tg of 140°C. The Pb and In concentrations in the solidified layer (without barrier layer) were the same as in Example 1. The same stability test as Example 1 was performed again, and the optical parameters changed as follows: These results show that compared to Example 1, the higher T _g of the solid polymer of the free-standing film results in a decrease in the stability of the green perovskite crystals at high blue flux (as can be seen from the decrease in the y value of the green intensity reduce). Therefore, QD film systems with low T _g are advantageous, which lead to improved QD film stability under high blue flux, so as to have stable color coordinates and stable white points during the operating life of the display device. Example 2 : Preparation of red core-shell quantum dots with low haze and thus spatial separation of green perovskite crystals: Green perovskite QDs from Example 1 were used. Film formation : 0.1 g of the green ink from Example 1 was mixed with a UV curable monomer/crosslinker mixture (0.7 g FA-513AS, Hitachi Chemical, Japan/0.3 g Miramer M240, Miwon, Korea) in a high speed mixer , the mixture contains 1 wt% photoinitiator diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide (TCI Europe, Netherlands) and 2 wt% polymer scattering particles (organic polysiloxane alkane, ShinEtsu, KMP-590) and the toluene was evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was then coated with a layer thickness of 50 microns on a 100 micron barrier film (Supplier: I-components (Korea); Product: TBF-1007) and then UV cured in a nitrogen atmosphere. A red coating formulation was then prepared by combining the red core-shell quantum dots with InP core and ZnS shell from Experiment 1 (suspended in toluene) with the UV curable monomer/crosslinker mixture (0.7 g FA-DCPA, Hitachi Chemical, Japan/0.3g Miramer M240, Miwon, Korea) was mixed in a high-speed mixer, and the mixture contained 1 wt% photoinitiator diphenyl (2,4,6-trimethylbenzyl hydroxyl)phosphine oxide (TCI Europe, Netherlands) and 2 wt% polymer scattering particles (organopolysiloxane, ShinEtsu, KMP-590), and toluene was evaporated by vacuum (<0.01 mbar) at room temperature. The resulting mixture was then coated with a layer thickness of 50 microns on the previously deposited green layer, a second barrier film was then laminated on top and the entire sandwich was UV cured for 60 seconds (UVAcube100, equipped with mercury lamp and quartz filter , Hoenle, Germany). The final self-supporting film showed optical properties comparable to Experiment 1. The Pb concentration in the cured green layer (no barrier layer) was 500 ppm Pb, and the Pb loading per area was 30 mg Pb/m ² . The In concentration in the cured red layer (no barrier layer) was 1300 ppm In, and the In loading per area was 80 mg In/ ^m2 . The changes in optical parameters are as follows: These results show that when tested under high blue flux and high temperature/high humidity conditions, both green perovskite crystals and red core-shell quantum dots show high stability, and it is possible to obtain natural films with separated green and red layers. Support luminous film. Example 3 : A self-supporting film was prepared as in Example 1, but using a red core-shell quantum dot platelet with a CdSe core and ZnS shell. The same experimental procedure as described in Example 1 was used, but with a thin layer of red core-shell quantum dots with a CdSe core and ZnS shell. The Pb concentration in the solidified layer (without barrier layer) was 500 ppm Pb, and the Pb loading per area was 30 mg Pb/m ² . The Cd concentration in the solidified layer (without barrier layer) was 500 ppm Cd, and the Cd loading per area was 30 mg Cd/m ² . The result is optical performance and stability comparable to Example 1. Example 4 : A self-supporting film was prepared as in Example 2, but using a red core-shell quantum dot platelet with a CdSe core and ZnS shell. The same experimental procedure as described in Example 2 was used, but with a thin layer of red core-shell quantum dots with a CdSe core and ZnS shell. The result is optical performance and stability comparable to Example 2.

1: Green luminous crystal 2:Red luminous crystal 3:Polymer 4: Barrier layer 5:LCD display area 6:LED 11:First area 21:Second area 100: Solid polymer composition

The invention will be better understood, and objects in addition to the above-described objects will become apparent from the following detailed description thereof. This description refers to the accompanying drawing, in which: [Fig. 1] A schematic diagram showing a solid polymer composition according to an embodiment of the present invention; [Fig. 2] A schematic diagram showing a self-supporting film according to an embodiment of the present invention; [Fig. 3] shows a light-emitting device according to an embodiment of the present invention; and [Fig. 4] A schematic diagram showing a self-supporting film according to another advantageous embodiment of the present invention.

1: Green luminous crystal

2:Red luminous crystal

3:Polymer

4: Barrier layer

100: Solid polymer composition

Claims (21)

A self-supporting film having a thickness of 0.005 to 10 mm, comprising: - a green luminescent crystal (1), and - a red luminescent crystal (2), and - a polymer (3) comprising an acrylate, wherein the green luminescent crystal (1) It is a perovskite crystal, which is selected from the compounds of formula (I): [M ¹ A ¹ ] _a M ² _b X _c (I), where: A ¹ represents one or more organic cations, and M ¹ represents One or more alkali metals, M ² represents one or more metals other than M ¹ , X represents one or more anions selected from the group consisting of halides, pseudohalides and sulfides, a represents 1 to 4, b represents 1 to 2, c represents 3 to 9, and there is M ¹ , or A ¹ , or M ¹ and A ¹ ; wherein the red luminescent crystal (2) has a sphalerite or wurtzite crystal structure and is selected from the formula Compound (II): [M ³ M ³ '][YY'] (II), where: M ³ and M ³ ' represent Al, Ga, In, and Y, Y' represent N, P, As, Sb, and M ³ ' and Y' may or may not exist, or M ³ and M ³ ' represent Zn, Cd, Be, and Y and Y' represent S, Se, Te, and M ³ ' and Y' may or may not exist exists, and wherein the concentration of M ² is 5 to 200 mg/m ² , and wherein the concentration of M ³ + M ³ ' is 30 to 250 mg/m ² . The self-supporting film of claim 1, wherein the polymer (3) has a molar ratio z of the sum of (oxygen + nitrogen) to carbon, wherein z is 0.9 or less. For example, the self-supporting film of claim 1 or 2, the haze h ₁ of the self-supporting film is 10

h ₁

80%. The self-supporting film of claim 1 or 2, which includes scattering particles selected from the group consisting of metal oxide particles and polymer particles. The self-supporting film of claim 1 or 2, wherein the solid polymer composition (100) is sandwiched between two barrier layers (4). The self-supporting film of claim 1 or 2, wherein the green luminescent crystal (1) is a perovskite crystal having formula (I'): FAPbBr ₃ (I'). The self-supporting film of claim 1 or 2, wherein the red luminescent crystal (2) is of core-shell type, wherein the core is as defined in claim 1 and has formula (II), and wherein the shell includes the formula ( III) Compound M ⁴ Z(III), wherein: M ⁴ represents Zn or Cd, and Z represents S, Se, Te, and the compounds of formula (III) and formula (II) are different. The self-supporting film of claim 1 or 2, wherein the red luminescent crystal (2) includes a core selected from the group consisting of InP and CdSe, and includes a shell or multiple shells selected from the group consisting of InP and CdSe. Free group consisting of ZnS, ZnSe, ZnSeS, and ZnTe, and their combinations. The self-supporting film of claim 1 or 2, wherein the polymer (3) contains cyclic aliphatic acrylate. The self-supporting film of claim 1 or 2, wherein the green luminescent crystal (1) is disposed in the first region (11) of the self-supporting film, and the red luminescent crystal (2) is disposed in the self-supporting film In the second region (21), the first region (11) and the second region (21) form adjacent layers. A solid polymer composition (100), which includes: - green luminescent crystal (1), and - red luminescent crystal (2), and - polymer (3), wherein the green luminescent crystal (1) is perovskite Crystals selected from compounds of formula (I): [M ¹ A ¹ ] _a M ² _b X _c (I), wherein: A ¹ represents one or more organic cations, M ¹ represents one or more alkali metals, M ² represents one or more metals other than M ¹ , X represents one or more anions selected from the group consisting of halides, pseudohalides and sulfides, a represents 1 to 4, b represents 1 to 2, c represents 3 to 9, and wherein M ¹ , or A ¹ , or M ¹ and A ¹ are present; wherein the red luminescent crystal (2) has a sphalerite or wurtzite crystal structure and is selected from compounds of formula (II): [ M ³ M ³ '][YY'](II), where: M ³ and M ³ ' represent Al, Ga, In, and Y and Y' represent N, P, As, Sb, and M ³ ', Y' May exist or may not exist, or M ³ and M ³ ' represent Zn, Cd, Be, and Y, Y' represent S, Se, Te, and M ³ ', Y' may exist or may not exist, and wherein M ² The concentration is 100 to 1000ppm. Such as the solid polymer composition (100) of claim 11, wherein the green luminescent crystal (1) is a perovskite crystal having formula (I'): FAPbBr ₃ (I'). The solid polymer composition (100) of claim 11 or 12, wherein the red luminescent crystal (2) is of core-shell type, wherein the core is as defined in claim 11 and has formula (II), and wherein The shell contains compound M ⁴ Z(III) of formula (III), wherein: M ⁴ represents Zn or Cd, and Z represents S, Se, Te, and the compounds of formula (III) and formula (II) are different. The solid polymer composition (100) of claim 11 or 12, wherein the red luminescent crystal (2) includes a core selected from the group consisting of InP and CdSe, and includes a shell or multiple shells, the shell Or the multi-shell system is selected from the group consisting of ZnS, ZnSe, ZnSeS, and ZnTe, and combinations thereof. Such as the solid polymer composition (100) of claim 13, wherein the concentration of M ³ + M ³ ' is 300 to 2,500 ppm, and/or the core-shell red luminescent crystal (2) has a thin layer structure. The solid polymer composition (100) of claim 11 or 12, wherein the polymer (3) has a molar ratio z of the sum of (oxygen + nitrogen) and carbon, where z

0.4. The solid polymer composition (100) of claim 11 or 12, wherein the polymer (3) contains acrylate. The solid polymer composition (100) of claim 11 or 12, wherein the solid polymer composition (100) has a glass transition temperature T _g of T _g

120℃. The solid polymer composition (100) of claim 11 or 12, wherein the solid polymer composition (100) includes scattering particles selected from the group consisting of metal oxide particles and polymer particles. A light-emitting device comprising the self-supporting film according to any one of the preceding claims 1 to 10, or the solid polymer composition according to any one of the preceding claims 11 to 19. The light-emitting device of claim 20, which includes one or more arrays of blue LEDs (6), wherein the array of LEDs (6) substantially covers the entire liquid crystal display area (5), and wherein the one or more blue LEDs (6) A diffusion plate is arranged between the array of LEDs (6) and the self-supporting film.

Images